CA1055759A - Production of planographic printing patterns - Google Patents
Production of planographic printing patternsInfo
- Publication number
- CA1055759A CA1055759A CA219,697A CA219697A CA1055759A CA 1055759 A CA1055759 A CA 1055759A CA 219697 A CA219697 A CA 219697A CA 1055759 A CA1055759 A CA 1055759A
- Authority
- CA
- Canada
- Prior art keywords
- silver halide
- image
- processing liquid
- aluminium
- alkaline aqueous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/06—Silver salts
- G03F7/07—Silver salts used for diffusion transfer
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Abstract
A b s t r a c t A process of producing a planographic printing plate according to the silver complex diffusion transfer process is described wherein a light-sensitive silver halide ma-terial is exposed and treated while in contact with an]
aluminium sheet or foil or supported aluminium layer serving as image receiving material, with an aqueous al-kaline processing liquid to cause development of the exposed silver halide, to cause unexposed and undeveloped silver halide to become complexed by a silver halide complexing agent and to transfer said complexed silver halide to the said image-receiving material where it is converted to a silver image in the presence of development nuclei characterised in that the said aqueous alkaline processing liquid contains at least one compound of the formula :
MOOC-X-COOM
wherein X is either -CH=CH, , , or
aluminium sheet or foil or supported aluminium layer serving as image receiving material, with an aqueous al-kaline processing liquid to cause development of the exposed silver halide, to cause unexposed and undeveloped silver halide to become complexed by a silver halide complexing agent and to transfer said complexed silver halide to the said image-receiving material where it is converted to a silver image in the presence of development nuclei characterised in that the said aqueous alkaline processing liquid contains at least one compound of the formula :
MOOC-X-COOM
wherein X is either -CH=CH, , , or
Description
~ ~ 5~75~
The present invention is concerned with photographic image-forming processes and materials used in the well-known silver complex diffusion transfer process to form planographic patterns on either an aluminlum sheet, foil or plate or an aluminium covered support.
The principle of silver complex diffusion transfer has been described e.g. in the Un:Lted States Pa-tent ~pecification
The present invention is concerned with photographic image-forming processes and materials used in the well-known silver complex diffusion transfer process to form planographic patterns on either an aluminlum sheet, foil or plate or an aluminium covered support.
The principle of silver complex diffusion transfer has been described e.g. in the Un:Lted States Pa-tent ~pecification
2,352,014 and has been explained in detail in "Photographic Silver ~alide Diffusion ~ransfer Processes" by A.Rott and E.
Weyde - Focal Press London, ~ew York 1972 and in the references cited therein.
In the silver complex diffusion transfer process, silver complexes are transferred image-wise by diffusion from a light-sensitive silver halide emulsion layer to an image-receiving layer, where the said silver complexes are converted optionally in the presence of development nuclei into a silver image~
For this purpose it is usual for an image-wise exposed silver halide emulsion layer of one material to be brought into contact with an image-receiving layer of a separate material in the presence of a developing substance or a development-activating substance and a so-called silver halide solvent converting the non-exposed silver halide into soluble silver complexes. In the exposed parts of the silver halide emulsion layer, -the silver halide is reduced by development to silver metal so that it cannot dissolve nor diffuse anymore~
In the non exposed parts of the silver halide e~ulsion layer, the silver halide is dissolved and converted into soluble GV.794 PCT
~ :., . . ., . ~ , : ;,., . ........................ . i -,: .
~ ' ': ', .~ ' ' . .' ' , ~ 57Si~
silver complexes, which are transferred to the image-receiving layer where the~ form metallic silver~ optionall~ in the presence of development nuclel and/or development agent or development-activating substances.
Silver complex diffusion transfer processes are widely used in all ~ields of reproduction work ei-ther to reproduce line originals or continuous tone originals. Details about these sub~ects can been found e.g. in the above cited book by A.Rott and ~.Weyde, in J.O.S.A. Vol. 37 no. 27 1947 and in the Canadian Patent Application 203,0l6.
Silver complex diffusion is also used with good success in the preparation of planographic printing plates to form on the printing member areas having differentiated water-repellen-t and water-accepting characteristics. In this so-called offset prin-ting field there are different ways to form the printing surface and make it ready for printing. ~or instance some methods use a light-sensitive member, which is exposed to the original and a separate image-receiving member for receiving the imagç formed according to the silver complex diffusion transfer process, whereas other methods use so-called mono-sheet materials wherein the light-sensitive layer and the image-receiving la~er form parts of one memberO
Once the image-receiving layer carries the transferred image i.e. as soon as the diffusion transfer process has come to an end, the image pattern formed is trea-ted with a lithographic fixer solution to strengthen the differentiated GV.794 PC~ - - 2 -~ , .
.. . . . ~ ; .. ~ -, .
~ 5~i7~
h~drophilic and hydrophobic areas of -the printing member.
Additionally, -the printing characteris-tics can be improved yet by treating the image pattern with a lacquer as described e.g. in United States Pa-tent Specification 3,378,372.
~ upports used in planographic printing may be composed of a wide variety of materials provided that -they possess the required characteristics of rigidity, dimensional stability, dependability in hydrophilic and hydrophobic circumstances~
etc.
1~ Suitable supports are aluminium pla-tes,foils or sheets and aluminium layer covered suppor-ts, the aluminium layer being deposited b~ lamination, vacuum deposition or other suitable means.
Planographic printing plates, using aluminium suppor-ts or aluminium-covered supports, can be divided mainly into two classes~ viz. a class in which the aluminium ~oil, sheet or other member or the aluminium metal layer (either or not eloxated) has been provided with development nuclei, and a class in which no development nuclei are used.
~he production of image~wise exposed planographic printing platescomprising an aluminium s~pport or an aluminium~
covered support, the aluminium support or the aluminium co~ering la~er of the support as the case may be containing no development nuclei, has been described in the Belgian Patent Specifica-tion 572,336.
In the method according ~ this Belgian Patent ~pecifi-cation the transferred silver complexes are not converted into GV.794 PCT - 3 -S~
metallic silver by spontaneous photographic development as is the case in the commonl~ known silver complex diffusion transfer process, but rather by electrolytic reduction, similar to what takes place when a solution of noble metal ions is brought into contact with -the surface o~ a less noble metal. An image is formed on the aluminium surface because the soluble silver ions are removed from the reaction medium, to form a silver image as a result of the diminution in concentration of silver salts at such surface. According to the disclosed process, the aluminium providing the plate surface should have a certain degree of impurity, because when the aluminium has too high a degree of purity, the ah-chorage of the silver image onto the aluminium is impairedO
The deposition and anchorage of silver images onto aluminium surface according to the diffusion transfer process is possible only after the aluminium oxide layer o~ the surface of the aluminium has been removed .
Such an aluminium oxide layer spontaneously forms on the surface of an aluminium plateg sheet, foil or covering layer when the aluminium is exposed to air. '~his phenomenon is undesirable in the above described process and therefore this aluminium oxide layer shoula be removed or caused to be con-vertedO ~he removal or conversion of said ~mdesired aluminium oxide layer can be ach~ed by dissolution in a processing medium containing alkaline substance and a solvent medium for the non-exposed silver halide~ ~he removal should take place prior to contact of the light-sensitive material with -the GV '~94 PC~ _ 4 _ ~ 3S5~75~
image-receiviIlg ~ember consisting of an aluminium plate, foil or sheet OI` a s~ort providèd ~ith an alumini1lm layer, otherwise on~y a par-t or none of the comp~exed silver complex would ~e reduced on the aluminium or aluminium covered support, resulting in a fain-t image or a total absence of image on the planograph printing member.
The aluminium oxide layer can be removed or converted by treating it with an alkaline solution. As a result of the chemical reaction between these components an alkaline aluminate is formed. When the alkaline processing solution is repeatedly used it becomes more and more contaminatecl witl alkaline aluminate so that the reac-tion speed decreases and after a certain time the solution loses its power to act on aluminium oxide. In other words the treating liquid is exhausted. Since no more alkaline aluminate sal-t can be formed, the liquid can no longer remove an aluminium oxide layer on an aluminium or aluminium covered image-receivlng member. ~he eiectrochemical reaction between the Al ions and silver -thiosulphate ions to form metallic silver becomes impossible.
m~ present invention will be found to counteract or reduce the exhaustion of an alkaline processing medium used in a s:ilver complex diffusion transfer process.
m e invention also provides an alkaline aqueous liquid for use in the formation of a dlffusion transfer image on aluminium sheet or an aluminium coated support serving for planographic printing.
GV.794 PC~ _ 5 _ ~ , ' ' :- . - -:: . .. . . . . : . : : : . . . . . . .: . . .. -. . ~: . .. - . :
l~5~S~
According -to the present inven-tion, in a silver complex diffusion transfer process using a processing li~uid con-taining at least one alkaline subs-tance and a silver halide solvent preferably a thiosulphate complexing agen-t for forming a diffusion transfer image on an aluminium support or supported aluminium layer -to produce a planographic printing plate, the processing liquid used contains at least one compound being within the scope of -the following formula : MOOC-X-COOM
wherein :
X is either -CH=CH-, ~ ~ / and M is an alkali metal.
It has been established experimentally -that -the presence of one or more of said compounds as specified above prolonges the treating power of the alkaline liquid. A given ~uantit~
of alkaline processing liquid can therefore be used in the production of a larger number of planographic printing plates.
Preferabl~ the alkaline processing liquid has a pH-value between 12.5 and 13.1. ~he compounds identified above are particularly effective under those conditionsO ~he efficacy of the said compounds appears to be best when the processing liquid is kept at a temperature between 18 and 28~.
Preferably the silver halide material and the image-receiving aluminium support or aluminium support layer are kept in close contact for at least 5 secondsO
GV.79~ PC~ - 6 -, - . . ~ .. ., . . - . . . ~ . . . . .. . . . . .
55~
According -to a preferred embodi~ent the processing liquid con-tains a compo~nd according -to the above general formula in an amo~rt equivalent to a-t least 2.5 g/l of -the acid form of that co~pound.
Preferably ph~alic or maleic acids are added to the alkaline processing liquid for the result aimed at.
According to a preferred embodiment the pH~value of the processing liquid is between 1205 and 13.1 by the presence of sodium or lithium hydroxide.
The processing liquid used in -the process of the present invention may contain in addition to an alkaline substance, - e.g. sodium hydroxide, potassium hydroxide or lithium hydroxide, a preserving agent, e.g. sodium sulphite, a thickening agent e.g. hydroxyethylcellulose or carboxyme-thylcellulose, a fog-inhibiting agent such as potassium bromide and, if necessary developing agents, such as hydroquinone and 1-phenyl-3-pyra-~olidinone, development nuclei, and silver halide solvents e.g.
sodium thiosulphate. ~he processing liquid need not contain ; developing agent(s) if the li~ht-sensitive layer or a layer in water-permeable relationship therewith contains appropriate developing agentts). In that case the proces~g liquid is not a developing composition properly so-called but an activating liquid.
It is believed that an alkaline aluminate salt formed as a result of a reaction between an aluminium oxide surface layer and ~ alkaline processing solution, is complexed by - GV.794 PC~ _ 7 _ ,' 57~
at least one of the compounds as above specified, -thus preven-ting the formation of ever increasing amounts of alkaline alumina-te salt and further preventing the said reaction mechanism from coming to an end a-t any early s-tage. However, the invention is not dependent on any theory or explanation.
~ he light-sensitive silver halide material used in per-forming the present invention contains at least one silver halide emulsion layer coated on at least one side of a support.
As emulsion layer suitable for use in the method according to the present invention an~ ligh-t-sensitive silver halide emulsion, either negative or direct-positive, can be used provided the de-velopment of the image-wise exposed light-sensitive silver halide layer proceeds sufficien-tly fast and a satisfactory complex formation of the non-developed silver halide is obt;ained. In view of these re~uire~en-ts and in order to obtain a satisfactory gradation necessary for graphic pur-poses, in practice mainly silver chloride emulsions are used, which may contain bromide and iodide or mixtures thereof or o-ther ingredients necessary for obtaining the desired emulsion characteristics. ~he light-sensitive emulsion layer con-taining silver halide is preferably unhardened.
~ he binder for the light sensitive material is preferably gelatin. However, the gelatin may be replaced wholly or partly by other natural and/or synthetic hydrophilic colloids e.g. albumin, casein or zein, polyvinyl alcohol, sodium salts of alginic acids1 sodium salts of cellulose derivatives such as GV~794 PC~ - 8 -.. : .: . . , . .: . ., .i ... ; ... : . . . . . . .. .. , .. ~ , ~ L~5~i75~
sodium salt o~ carbo.~ymethylcel:Lulose.The emulsion layer and/or one or more layers in water-permeable relationship with the sil-ver halide emulsion layer may comprise any of the compounds customarily used in such :Layers :Lor carrying out the silver complex diffusion transfer process. ~hese compounds include e.g. developing agents such as hydroquinone, preferably in ~Q amount of 0.3 to 3 g~sq.m and/or 1--phenyl-4-methyl-3-pyraz~lidlnone, preferably in an amount of 0.075 to 0O75 g/sq.m-;
also coating agents, stabilizing agents, antifogging agents, plasticizers,development accelerators e.g. polyoxyalkylene compo~ds and onium compounds, spectral sensitizing agents, etc.
'rhe emulsion is usually coated on a support in such a way that the amount of silver present in the resulting light-sensitive layer is equivalent witn an amount of silver nitrate of approximatively 0.5 to approximatively 3.5 g/sq.m. ~he support ~or the light-sensitive silver halide emulsion ~ay be any of the supports custo~arily e~ployed in the art, e.g. a support of paper, glass,fil~ e.g.
cellulose acetate film, pol~vinyl acetal film, polystyrene film, polyethylene terephthalate film, metal, metalized paper or metal/paper laminate Paper supports coated on one or both sides with an ~-olefin polymer e.g.
polyethylene can also be used. In order to compensate for the curling tendency of the liæht-sensitive material one side of the support can be coated with a polyethylene layer, whose spe-cific density and/or thicXness differs from that on the other side of the support. The compensation for the curling tendency GV.794 PC~ _ 9 _ , . .
~575~
of the material can also be improved by incorporation of matting ag~nts into th~se coa-tings.
~ he emulsion-coated side of -the support of the light-se~sitive ~aterial can be provided with a top layer, which may be a layer free from gelatin and containing a water~
permeable colloid. ~he top layer is of such nature that the diffusion is not inhibited or restrained and that it acts e.g. as an antistress layer. Appropriate wa-ter-permeable binding agents for the layer coated on top of the light-sensitive silver halide emulsion layer are e.g. methylcellulose, the sodium salt of earboxymethylcellulose, hydroxyethyl~
cellulose, hydroxyethyl starch, hydroxypropyl starch, sodium alginate, gum tragacanth, starch, polyvinyl alcohol, poly-acrylic acid, polyacrylamide, polyvinyl pyrrolidone, poly-oxyethylene, copoly(methylvinylether/maleie acid), ete.
The thiekness of a said -top layer may vary aceording to the nature of the colloid used~ ~ueh layer, if present, may be transferred at leas-t partially -to the image-recei~ing material when the diffusion process comes to an end.
~he image-receiving material according to the present invention comprise an aluminium-sheet, foil, plate or the like or any other kind of support bearing an aluminium layer which has been applied by any suitable teehnique e.g. lamination vaeuum deposition ete.
.
GV.794 PCT - 10 -.
~L~557~i~
In the silver complex diffusion transfer process according to the present invention use can be made of separate ligh-t-sensitive and image-receiving materials which are brought into contact to permit the dif~usion to -ta~e place. ~he sequence of layers can be chosen in relation to the end result aimed at.
For more particulars about exposure and developing apparatus, ~hich may be applied in a process according to the present invention as well as particulars on -the silver halide diffusion process in general there can be referred to "Photographic Silver Halide Diffusion Processes", by A~Rott and ~.Weyde, ~ocal Press ~ondon, ~ew-York 1972 and to the patent literature cited therein.
Other features of the present invention will become appa-rent upon examination of the following examplesO
Exam~le 1 Cadmium chloride is added to a silver chloride emulsion ready for coating in such a way that the coated emulsion layer contains 1.43 g of silver and 0.51 g of cadmium per sq.m. ~he emulsion is coa-ted on a baryta-coated paper base and the light-sensitive paper thus obtained is image-wise exposed. ~he exposed negative and an aluminium sheet consisting of 99.5 %
of aluminium and 0.5 % of magnesium and silicone, the surface of which is brushed to grain depths of 2 to 4 ~ are passed through a usual apparatus for carrying ou-t the diffusion transfer process. ~his apparatus contains an aqueous deve loper solution of the following composition :
GV.794 PC~
. . . . .. . - . ......................... -. , ., . ~ , , ., ~ -. , -- . . .; . . . : - ~ ~
~S75~
sodium hydroxide 11.5 g sodium sulphite 90 g sodium thiosulphate 3.5 g pota~ . bromide 0-75 g hydroquinone 10 g l-phenyl-3-pyrazolidinone ~l.5 g trisodium salt o~ ethylene diamine -tetraacetic a~d 3.5 g carbo-~ymethylcellulose 10 g water to make 1000 ml pH value 13.1 ~he negative and the aluminium plate are passed through -this solution and brought into contact between rubber rollers.
q'he paper sheet carr~ing the emulsion layer is separated from the aluminium sheet, thus leaving a silver image on the aluminium sheet. ~he sil~er image firmer adheres to the surface o~ said alumini~lm sheet. Immadiately thereafter, the sheet bearing the image is rubbed for approximatively 30 seconds with a cloth soaked with a lithographic preparation having the following composition :
carboxymethylcellulose 3.24 g sodium phosphate 0.6 g phosphoric acid o.~ g n-hexaclecyl trimethyl ammonium bromide 0.06 g 10 % aqueous solution of Pormalde-h~de 1 g water to make 100 ml ~he lithographic printing plate is now ready Por use.
GV.794 PC~ - 12 -5 ~
~ he dev~loper described i~ thi~ example is capable of ~rocessing 55 aluminium pla~es having a size of 254 x 381 mm, provided all of them are proce~sed one after the other ~ that the effect of exhaustion by aerial oxidation or e~haustio~ by long~ standing between the different processing ~eri.ods of the plates is reduced to a minimum.
-E~mple 2 Example 1 is repeated with the same ingredients, proportions and conditions except ~or the use of 10 g of maleic acid per liter of developer and the adjustment of the pH value of the said developer to 13.1. ~his pX value is obtained b~ increasing the amount of sodium h~droxide to 18 g/liter of developer.
In these conditions it is possible to process 99 aluminium plates of the same size as described i.~ example 1.
Example ~
Exa~ple 1 is repeated with the same ingredi~nts propor-tions, and conditions, except for the use of 20 ~ of phthalic acid per liter of de~eloper and the adjustment o~ the pH ~alue to 13~1 by increasi~ the amount of sodium h~droxide to 21.5 g per liter of developer.
In ~hese conditio~s it is possible to process 99 aluminium plates of the same size as in example 1.
.
Ex~mple 1 is repeated with the same i~gredients propor-tio~s~ and co:~ditions~ except for the use of 20 g of di-carboxyp~ridina per liter of-developer and the adjustment of ~ ~V.79~ PC~
:- ~ - , . :. , - .
.~ , . .. . ..
-~5~7~
the pH value to 13.1 by increasing the amount of sodium hydroxide to 24 g per li-ter of developer.
In these conditions it is possible to process 99 aluminium plates of the same size as in example 1.
Example 5 ~ xample 1 is repeated with the same ingredients propor-tions, and conditions, except for the use of 5 g of pyro-mellitic acid per liter of developer and the adjustment of the pH value to 13.1 by increasing the amount of sodium hydroxide to 19 g per liter of developer.
In these conditions it is possible to process 99 aluminium plates of the same size as in example 1.
:: .
GV.794 PC~ - 14 -.. .- . : . ., . . - . .
Weyde - Focal Press London, ~ew York 1972 and in the references cited therein.
In the silver complex diffusion transfer process, silver complexes are transferred image-wise by diffusion from a light-sensitive silver halide emulsion layer to an image-receiving layer, where the said silver complexes are converted optionally in the presence of development nuclei into a silver image~
For this purpose it is usual for an image-wise exposed silver halide emulsion layer of one material to be brought into contact with an image-receiving layer of a separate material in the presence of a developing substance or a development-activating substance and a so-called silver halide solvent converting the non-exposed silver halide into soluble silver complexes. In the exposed parts of the silver halide emulsion layer, -the silver halide is reduced by development to silver metal so that it cannot dissolve nor diffuse anymore~
In the non exposed parts of the silver halide e~ulsion layer, the silver halide is dissolved and converted into soluble GV.794 PCT
~ :., . . ., . ~ , : ;,., . ........................ . i -,: .
~ ' ': ', .~ ' ' . .' ' , ~ 57Si~
silver complexes, which are transferred to the image-receiving layer where the~ form metallic silver~ optionall~ in the presence of development nuclel and/or development agent or development-activating substances.
Silver complex diffusion transfer processes are widely used in all ~ields of reproduction work ei-ther to reproduce line originals or continuous tone originals. Details about these sub~ects can been found e.g. in the above cited book by A.Rott and ~.Weyde, in J.O.S.A. Vol. 37 no. 27 1947 and in the Canadian Patent Application 203,0l6.
Silver complex diffusion is also used with good success in the preparation of planographic printing plates to form on the printing member areas having differentiated water-repellen-t and water-accepting characteristics. In this so-called offset prin-ting field there are different ways to form the printing surface and make it ready for printing. ~or instance some methods use a light-sensitive member, which is exposed to the original and a separate image-receiving member for receiving the imagç formed according to the silver complex diffusion transfer process, whereas other methods use so-called mono-sheet materials wherein the light-sensitive layer and the image-receiving la~er form parts of one memberO
Once the image-receiving layer carries the transferred image i.e. as soon as the diffusion transfer process has come to an end, the image pattern formed is trea-ted with a lithographic fixer solution to strengthen the differentiated GV.794 PC~ - - 2 -~ , .
.. . . . ~ ; .. ~ -, .
~ 5~i7~
h~drophilic and hydrophobic areas of -the printing member.
Additionally, -the printing characteris-tics can be improved yet by treating the image pattern with a lacquer as described e.g. in United States Pa-tent Specification 3,378,372.
~ upports used in planographic printing may be composed of a wide variety of materials provided that -they possess the required characteristics of rigidity, dimensional stability, dependability in hydrophilic and hydrophobic circumstances~
etc.
1~ Suitable supports are aluminium pla-tes,foils or sheets and aluminium layer covered suppor-ts, the aluminium layer being deposited b~ lamination, vacuum deposition or other suitable means.
Planographic printing plates, using aluminium suppor-ts or aluminium-covered supports, can be divided mainly into two classes~ viz. a class in which the aluminium ~oil, sheet or other member or the aluminium metal layer (either or not eloxated) has been provided with development nuclei, and a class in which no development nuclei are used.
~he production of image~wise exposed planographic printing platescomprising an aluminium s~pport or an aluminium~
covered support, the aluminium support or the aluminium co~ering la~er of the support as the case may be containing no development nuclei, has been described in the Belgian Patent Specifica-tion 572,336.
In the method according ~ this Belgian Patent ~pecifi-cation the transferred silver complexes are not converted into GV.794 PCT - 3 -S~
metallic silver by spontaneous photographic development as is the case in the commonl~ known silver complex diffusion transfer process, but rather by electrolytic reduction, similar to what takes place when a solution of noble metal ions is brought into contact with -the surface o~ a less noble metal. An image is formed on the aluminium surface because the soluble silver ions are removed from the reaction medium, to form a silver image as a result of the diminution in concentration of silver salts at such surface. According to the disclosed process, the aluminium providing the plate surface should have a certain degree of impurity, because when the aluminium has too high a degree of purity, the ah-chorage of the silver image onto the aluminium is impairedO
The deposition and anchorage of silver images onto aluminium surface according to the diffusion transfer process is possible only after the aluminium oxide layer o~ the surface of the aluminium has been removed .
Such an aluminium oxide layer spontaneously forms on the surface of an aluminium plateg sheet, foil or covering layer when the aluminium is exposed to air. '~his phenomenon is undesirable in the above described process and therefore this aluminium oxide layer shoula be removed or caused to be con-vertedO ~he removal or conversion of said ~mdesired aluminium oxide layer can be ach~ed by dissolution in a processing medium containing alkaline substance and a solvent medium for the non-exposed silver halide~ ~he removal should take place prior to contact of the light-sensitive material with -the GV '~94 PC~ _ 4 _ ~ 3S5~75~
image-receiviIlg ~ember consisting of an aluminium plate, foil or sheet OI` a s~ort providèd ~ith an alumini1lm layer, otherwise on~y a par-t or none of the comp~exed silver complex would ~e reduced on the aluminium or aluminium covered support, resulting in a fain-t image or a total absence of image on the planograph printing member.
The aluminium oxide layer can be removed or converted by treating it with an alkaline solution. As a result of the chemical reaction between these components an alkaline aluminate is formed. When the alkaline processing solution is repeatedly used it becomes more and more contaminatecl witl alkaline aluminate so that the reac-tion speed decreases and after a certain time the solution loses its power to act on aluminium oxide. In other words the treating liquid is exhausted. Since no more alkaline aluminate sal-t can be formed, the liquid can no longer remove an aluminium oxide layer on an aluminium or aluminium covered image-receivlng member. ~he eiectrochemical reaction between the Al ions and silver -thiosulphate ions to form metallic silver becomes impossible.
m~ present invention will be found to counteract or reduce the exhaustion of an alkaline processing medium used in a s:ilver complex diffusion transfer process.
m e invention also provides an alkaline aqueous liquid for use in the formation of a dlffusion transfer image on aluminium sheet or an aluminium coated support serving for planographic printing.
GV.794 PC~ _ 5 _ ~ , ' ' :- . - -:: . .. . . . . : . : : : . . . . . . .: . . .. -. . ~: . .. - . :
l~5~S~
According -to the present inven-tion, in a silver complex diffusion transfer process using a processing li~uid con-taining at least one alkaline subs-tance and a silver halide solvent preferably a thiosulphate complexing agen-t for forming a diffusion transfer image on an aluminium support or supported aluminium layer -to produce a planographic printing plate, the processing liquid used contains at least one compound being within the scope of -the following formula : MOOC-X-COOM
wherein :
X is either -CH=CH-, ~ ~ / and M is an alkali metal.
It has been established experimentally -that -the presence of one or more of said compounds as specified above prolonges the treating power of the alkaline liquid. A given ~uantit~
of alkaline processing liquid can therefore be used in the production of a larger number of planographic printing plates.
Preferabl~ the alkaline processing liquid has a pH-value between 12.5 and 13.1. ~he compounds identified above are particularly effective under those conditionsO ~he efficacy of the said compounds appears to be best when the processing liquid is kept at a temperature between 18 and 28~.
Preferably the silver halide material and the image-receiving aluminium support or aluminium support layer are kept in close contact for at least 5 secondsO
GV.79~ PC~ - 6 -, - . . ~ .. ., . . - . . . ~ . . . . .. . . . . .
55~
According -to a preferred embodi~ent the processing liquid con-tains a compo~nd according -to the above general formula in an amo~rt equivalent to a-t least 2.5 g/l of -the acid form of that co~pound.
Preferably ph~alic or maleic acids are added to the alkaline processing liquid for the result aimed at.
According to a preferred embodiment the pH~value of the processing liquid is between 1205 and 13.1 by the presence of sodium or lithium hydroxide.
The processing liquid used in -the process of the present invention may contain in addition to an alkaline substance, - e.g. sodium hydroxide, potassium hydroxide or lithium hydroxide, a preserving agent, e.g. sodium sulphite, a thickening agent e.g. hydroxyethylcellulose or carboxyme-thylcellulose, a fog-inhibiting agent such as potassium bromide and, if necessary developing agents, such as hydroquinone and 1-phenyl-3-pyra-~olidinone, development nuclei, and silver halide solvents e.g.
sodium thiosulphate. ~he processing liquid need not contain ; developing agent(s) if the li~ht-sensitive layer or a layer in water-permeable relationship therewith contains appropriate developing agentts). In that case the proces~g liquid is not a developing composition properly so-called but an activating liquid.
It is believed that an alkaline aluminate salt formed as a result of a reaction between an aluminium oxide surface layer and ~ alkaline processing solution, is complexed by - GV.794 PC~ _ 7 _ ,' 57~
at least one of the compounds as above specified, -thus preven-ting the formation of ever increasing amounts of alkaline alumina-te salt and further preventing the said reaction mechanism from coming to an end a-t any early s-tage. However, the invention is not dependent on any theory or explanation.
~ he light-sensitive silver halide material used in per-forming the present invention contains at least one silver halide emulsion layer coated on at least one side of a support.
As emulsion layer suitable for use in the method according to the present invention an~ ligh-t-sensitive silver halide emulsion, either negative or direct-positive, can be used provided the de-velopment of the image-wise exposed light-sensitive silver halide layer proceeds sufficien-tly fast and a satisfactory complex formation of the non-developed silver halide is obt;ained. In view of these re~uire~en-ts and in order to obtain a satisfactory gradation necessary for graphic pur-poses, in practice mainly silver chloride emulsions are used, which may contain bromide and iodide or mixtures thereof or o-ther ingredients necessary for obtaining the desired emulsion characteristics. ~he light-sensitive emulsion layer con-taining silver halide is preferably unhardened.
~ he binder for the light sensitive material is preferably gelatin. However, the gelatin may be replaced wholly or partly by other natural and/or synthetic hydrophilic colloids e.g. albumin, casein or zein, polyvinyl alcohol, sodium salts of alginic acids1 sodium salts of cellulose derivatives such as GV~794 PC~ - 8 -.. : .: . . , . .: . ., .i ... ; ... : . . . . . . .. .. , .. ~ , ~ L~5~i75~
sodium salt o~ carbo.~ymethylcel:Lulose.The emulsion layer and/or one or more layers in water-permeable relationship with the sil-ver halide emulsion layer may comprise any of the compounds customarily used in such :Layers :Lor carrying out the silver complex diffusion transfer process. ~hese compounds include e.g. developing agents such as hydroquinone, preferably in ~Q amount of 0.3 to 3 g~sq.m and/or 1--phenyl-4-methyl-3-pyraz~lidlnone, preferably in an amount of 0.075 to 0O75 g/sq.m-;
also coating agents, stabilizing agents, antifogging agents, plasticizers,development accelerators e.g. polyoxyalkylene compo~ds and onium compounds, spectral sensitizing agents, etc.
'rhe emulsion is usually coated on a support in such a way that the amount of silver present in the resulting light-sensitive layer is equivalent witn an amount of silver nitrate of approximatively 0.5 to approximatively 3.5 g/sq.m. ~he support ~or the light-sensitive silver halide emulsion ~ay be any of the supports custo~arily e~ployed in the art, e.g. a support of paper, glass,fil~ e.g.
cellulose acetate film, pol~vinyl acetal film, polystyrene film, polyethylene terephthalate film, metal, metalized paper or metal/paper laminate Paper supports coated on one or both sides with an ~-olefin polymer e.g.
polyethylene can also be used. In order to compensate for the curling tendency of the liæht-sensitive material one side of the support can be coated with a polyethylene layer, whose spe-cific density and/or thicXness differs from that on the other side of the support. The compensation for the curling tendency GV.794 PC~ _ 9 _ , . .
~575~
of the material can also be improved by incorporation of matting ag~nts into th~se coa-tings.
~ he emulsion-coated side of -the support of the light-se~sitive ~aterial can be provided with a top layer, which may be a layer free from gelatin and containing a water~
permeable colloid. ~he top layer is of such nature that the diffusion is not inhibited or restrained and that it acts e.g. as an antistress layer. Appropriate wa-ter-permeable binding agents for the layer coated on top of the light-sensitive silver halide emulsion layer are e.g. methylcellulose, the sodium salt of earboxymethylcellulose, hydroxyethyl~
cellulose, hydroxyethyl starch, hydroxypropyl starch, sodium alginate, gum tragacanth, starch, polyvinyl alcohol, poly-acrylic acid, polyacrylamide, polyvinyl pyrrolidone, poly-oxyethylene, copoly(methylvinylether/maleie acid), ete.
The thiekness of a said -top layer may vary aceording to the nature of the colloid used~ ~ueh layer, if present, may be transferred at leas-t partially -to the image-recei~ing material when the diffusion process comes to an end.
~he image-receiving material according to the present invention comprise an aluminium-sheet, foil, plate or the like or any other kind of support bearing an aluminium layer which has been applied by any suitable teehnique e.g. lamination vaeuum deposition ete.
.
GV.794 PCT - 10 -.
~L~557~i~
In the silver complex diffusion transfer process according to the present invention use can be made of separate ligh-t-sensitive and image-receiving materials which are brought into contact to permit the dif~usion to -ta~e place. ~he sequence of layers can be chosen in relation to the end result aimed at.
For more particulars about exposure and developing apparatus, ~hich may be applied in a process according to the present invention as well as particulars on -the silver halide diffusion process in general there can be referred to "Photographic Silver Halide Diffusion Processes", by A~Rott and ~.Weyde, ~ocal Press ~ondon, ~ew-York 1972 and to the patent literature cited therein.
Other features of the present invention will become appa-rent upon examination of the following examplesO
Exam~le 1 Cadmium chloride is added to a silver chloride emulsion ready for coating in such a way that the coated emulsion layer contains 1.43 g of silver and 0.51 g of cadmium per sq.m. ~he emulsion is coa-ted on a baryta-coated paper base and the light-sensitive paper thus obtained is image-wise exposed. ~he exposed negative and an aluminium sheet consisting of 99.5 %
of aluminium and 0.5 % of magnesium and silicone, the surface of which is brushed to grain depths of 2 to 4 ~ are passed through a usual apparatus for carrying ou-t the diffusion transfer process. ~his apparatus contains an aqueous deve loper solution of the following composition :
GV.794 PC~
. . . . .. . - . ......................... -. , ., . ~ , , ., ~ -. , -- . . .; . . . : - ~ ~
~S75~
sodium hydroxide 11.5 g sodium sulphite 90 g sodium thiosulphate 3.5 g pota~ . bromide 0-75 g hydroquinone 10 g l-phenyl-3-pyrazolidinone ~l.5 g trisodium salt o~ ethylene diamine -tetraacetic a~d 3.5 g carbo-~ymethylcellulose 10 g water to make 1000 ml pH value 13.1 ~he negative and the aluminium plate are passed through -this solution and brought into contact between rubber rollers.
q'he paper sheet carr~ing the emulsion layer is separated from the aluminium sheet, thus leaving a silver image on the aluminium sheet. ~he sil~er image firmer adheres to the surface o~ said alumini~lm sheet. Immadiately thereafter, the sheet bearing the image is rubbed for approximatively 30 seconds with a cloth soaked with a lithographic preparation having the following composition :
carboxymethylcellulose 3.24 g sodium phosphate 0.6 g phosphoric acid o.~ g n-hexaclecyl trimethyl ammonium bromide 0.06 g 10 % aqueous solution of Pormalde-h~de 1 g water to make 100 ml ~he lithographic printing plate is now ready Por use.
GV.794 PC~ - 12 -5 ~
~ he dev~loper described i~ thi~ example is capable of ~rocessing 55 aluminium pla~es having a size of 254 x 381 mm, provided all of them are proce~sed one after the other ~ that the effect of exhaustion by aerial oxidation or e~haustio~ by long~ standing between the different processing ~eri.ods of the plates is reduced to a minimum.
-E~mple 2 Example 1 is repeated with the same ingredients, proportions and conditions except ~or the use of 10 g of maleic acid per liter of developer and the adjustment of the pH value of the said developer to 13.1. ~his pX value is obtained b~ increasing the amount of sodium h~droxide to 18 g/liter of developer.
In these conditions it is possible to process 99 aluminium plates of the same size as described i.~ example 1.
Example ~
Exa~ple 1 is repeated with the same ingredi~nts propor-tions, and conditions, except for the use of 20 ~ of phthalic acid per liter of de~eloper and the adjustment o~ the pH ~alue to 13~1 by increasi~ the amount of sodium h~droxide to 21.5 g per liter of developer.
In ~hese conditio~s it is possible to process 99 aluminium plates of the same size as in example 1.
.
Ex~mple 1 is repeated with the same i~gredients propor-tio~s~ and co:~ditions~ except for the use of 20 g of di-carboxyp~ridina per liter of-developer and the adjustment of ~ ~V.79~ PC~
:- ~ - , . :. , - .
.~ , . .. . ..
-~5~7~
the pH value to 13.1 by increasing the amount of sodium hydroxide to 24 g per li-ter of developer.
In these conditions it is possible to process 99 aluminium plates of the same size as in example 1.
Example 5 ~ xample 1 is repeated with the same ingredients propor-tions, and conditions, except for the use of 5 g of pyro-mellitic acid per liter of developer and the adjustment of the pH value to 13.1 by increasing the amount of sodium hydroxide to 19 g per liter of developer.
In these conditions it is possible to process 99 aluminium plates of the same size as in example 1.
:: .
GV.794 PC~ - 14 -.. .- . : . ., . . - . .
Claims (13)
1. A process of producing a planographic printing plate by forming a diffusion transfer image on an aluminium sheet or foil or on a supported aluminium layer serving as image receiving material wherein the diffusion transfer of silver complexes from an image-wise exposed light-sensitive silver halide material onto said image receiving material is brought about with an alkaline aqueous processing liquid containing at least one compound being within the scope of the following formula :
MOOC-X-COOM
wherein X is either :
-CH=CH-, , , or and M is an alkali metal.
MOOC-X-COOM
wherein X is either :
-CH=CH-, , , or and M is an alkali metal.
2. A process according to claim 1, wherein the exposed light-sensitive silver halide material and the image receiving material in the presence of said processing liquid are main-tained in contact for at least 5 seconds before they are separated.
3. A process according to claim 1, wherein the processing liquid has a pH value between 12.5 and 13.1.
4. A process according to any one of claims 1, 2 or 3 wherein the processing liquid has a temperature between 18°C and 28°C.
5. A process according to any one of claims 1, 2 or 3 wherein before forming the diffusion transfer image phthalic acid or maleic acid is added to the processing liquid.
6. A process according to any one of claim 1, 2 or 3 wherein the processing liquid contains a compound as identified in claim 1 in an amount equivalent to at least 2.5 g/l of the acid form of that compound.
7. A process according to and one of claims 1, 2 or 3 wherein the pH value of the processing liquid is between 12.5 and 13.1 by the presence of sodium or lithium hydroxide.
8. An alkaline aqueous liquid containing a thiosulphate complexing agent for silver halide and containing at least one compound within the scope of the following formula :
MOOC-X-COOM
wherein X is either -CH=CH-, , , or and M is an alkali metal.
MOOC-X-COOM
wherein X is either -CH=CH-, , , or and M is an alkali metal.
9. An alkaline aqueous liquid according to claim 8 wherein said compound is MOOC-CH=CH-COOM or wherein M is an alkali metal.
10. An alkaline aqueous liquid according to claim 8, wherein said compound is present in an amount of at least 2.5 g/l.
11. An alkaline aqueous liquid according to any one of claims 8, 9 or 109 wherein sodium hydroxide or lithium hydroxide is present.
12. An alkaline aqueous liquid according to any one of claims 8, 9 or 10 wherein said liquid contains a developing agent for silver halide photographic materials.
13. An alkaline aqueous liquid according to claim 8, having substantially the following composition :
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB5946/74A GB1484269A (en) | 1974-02-08 | 1974-02-08 | Photographic silver complex diffusion transfer processing liquid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1055759A true CA1055759A (en) | 1979-06-05 |
Family
ID=9805585
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA219,697A Expired CA1055759A (en) | 1974-02-08 | 1975-02-10 | Production of planographic printing patterns |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US3989521A (en) |
| JP (1) | JPS50113308A (en) |
| BE (1) | BE825142A (en) |
| CA (1) | CA1055759A (en) |
| FR (1) | FR2260817B1 (en) |
| GB (1) | GB1484269A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5321601A (en) * | 1976-08-10 | 1978-02-28 | Mitsubishi Paper Mills Ltd | Improved offset printing plate |
| JPS5321602A (en) * | 1976-08-10 | 1978-02-28 | Mitsubishi Paper Mills Ltd | Lithographic printing material applying silver complex salt diffusion transfer method |
| DE3265321D1 (en) | 1981-02-25 | 1985-09-19 | Agfa Gevaert Nv | Production of a planographic printing plate through the silver complex diffusion transfer process |
| DE69023180T2 (en) * | 1989-07-25 | 1996-06-13 | Agfa Gevaert Nv | Lithographic aluminum offset printing form produced by the DTR process. |
| US5213943A (en) * | 1989-07-25 | 1993-05-25 | Agfa-Gevaert, N.V. | Lithographic aluminum offset printing plate made according to the DTR-process |
| EP0519123B1 (en) * | 1991-06-20 | 1994-11-23 | Agfa-Gevaert N.V. | A method for making a lithographic aluminium offset printing plate by the silver salt diffusion transfer process |
| US5399457A (en) * | 1993-10-15 | 1995-03-21 | Minnesota Mining And Manufacturing Company | Process for reducing sludge in diffusion transfer printing plates |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE572336A (en) * | 1957-10-25 |
-
1974
- 1974-02-08 GB GB5946/74A patent/GB1484269A/en not_active Expired
-
1975
- 1975-02-04 BE BE1006438A patent/BE825142A/en unknown
- 1975-02-05 FR FR7504010A patent/FR2260817B1/fr not_active Expired
- 1975-02-08 JP JP50016781A patent/JPS50113308A/ja active Pending
- 1975-02-10 CA CA219,697A patent/CA1055759A/en not_active Expired
- 1975-02-10 US US05/548,755 patent/US3989521A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| GB1484269A (en) | 1977-09-01 |
| FR2260817B1 (en) | 1977-04-15 |
| BE825142A (en) | 1975-08-04 |
| JPS50113308A (en) | 1975-09-05 |
| FR2260817A1 (en) | 1975-09-05 |
| US3989521A (en) | 1976-11-02 |
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